Lateral spinous process spacer with deployable wings

ABSTRACT

Interspinous process implants are disclosed. Also disclosed are systems and kits including such implants, methods of inserting such implants, and methods of alleviating pain or discomfort associated with the spinal column.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/474,413 filed Sep. 2, 2014, which is a continuation of U.S. patentapplication Ser. No. 13/211,945, filed Aug. 17, 2011, now U.S. Pat. No.8,858,598, which is a continuation of U.S. patent application Ser. No.12/334,266, filed Dec. 12, 2008, now U.S. Pat. No. 8,021,393. Theseapplications are incorporated herein by reference in their entiretiesfor all purposes.

FIELD OF THE INVENTION

The present invention is generally directed to intervertebral orinterspinous process implants, systems and kits including such implants,methods of inserting such implants, and methods of treating spinalstenosis or for alleviating pain or discomfort associated with thespinal column.

BACKGROUND OF THE INVENTION

Occurrences of spinal stenosis are increasing as society ages. Spinalstenosis is the narrowing of the spinal canal, lateral recess or neuralforamen, characterized by a reduction in the available space for thepassage of blood vessels and nerves. Clinical symptoms of spinalstenosis include extremity pain, radiculopathy, myelopathy, sensory ormotor deficit, bladder or bowel dysfunction, and neurogenicclaudication. Pain associated with such stenosis can be relieved bysurgical or non-surgical treatments, such as medication, physicaltherapy, back braces and the like. While spinal stenosis is generallymore prevalent of the elderly, it can occur in individuals of all agesand sizes.

There is a need for implants that may be placed between spinal processesfor minimally or less invasive surgical treatment of spinal stenosisand, in particular, for implants that may be installed unilaterallyand/or without removal of the supraspinous ligament.

SUMMARY OF THE INVENTION

Certain embodiments of the present invention are generally directed tominimally or less invasive implants, in particular, interspinous processimplants or spacers. Other embodiments of the invention are furtherdirected to systems and kits including such implants, methods ofinserting such implants, and methods of alleviating pain or discomfortassociated with the spinal column.

Some embodiments of the present invention provide spacers or implantsand methods for relieving pain and other symptoms associated with spinalstenosis, by relieving pressure and restrictions on the blood vesselsand nerves. Such alleviation of pressure may be accomplished in thepresent invention through the use of an implant placed between thespinous process of adjacent vertebra.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more readily understood with reference to theembodiments thereof illustrated in the attached figures, in which:

FIG. 1 is a side perspective view of one embodiment of an implantaccording to the invention for creating, increasing, or maintainingdistraction between adjacent spinous processes;

FIG. 2 is a cross-sectional view of the implant of FIG. 1 shown in afirst position;

FIG. 3 is a side perspective view of the implant of FIG. 1 shown in asecond position;

FIG. 4 is a cross-sectional view of the implant of FIG. 1 shown in asecond position;

FIG. 5 is a proximal perspective view of the implant of FIG. 1 shown ina first position;

FIG. 6 is a distal end view of the implant of FIG. 1 shown in a firstposition;

FIG. 7 is a distal perspective view of the implant of FIG. 1 shown in asecond position;

FIG. 8 is a distal end view of the implant of FIG. 1 shown in a secondposition;

FIG. 9 is an exploded view of the implant of FIG. 1;

FIGS. 10-11 are perspective views of a wing member of the implant ofFIG. 1;

FIGS. 12-13 are perspective views of a barrel insert of the implant ofFIG. 1;

FIG. 14 is a perspective view of a central body of the implant of FIG.1;

FIG. 15 is a perspective view of a rotatable insert of the implant ofFIG. 1;

FIG. 16-20 are side views demonstrating various steps according to oneembodiment of a method of installation of the implant of FIG. 1;

FIGS. 21-22 are side and distal perspective views of another embodimentof an implant according to the invention, shown in a first positionextending over a guidewire;

FIGS. 23-24 are side and distal perspective views of the implant of FIG.21 shown in a second position;

FIGS. 25-26 are proximal perspective and distal end views of the implantof FIG. 21 shown in a second position;

FIGS. 27-28 are side and distal perspective views of another embodimentof an implant according to the invention, shown in a first positionextending over a guidewire;

FIGS. 29-30 are side and cross-sectional views of the implant of FIG. 27shown in a first position;

FIGS. 31-32 are side and distal perspective views of the implant of FIG.27 shown in a second position;

FIGS. 33-34 are distal end and cross-sectional views of the implant ofFIG. 26 shown in a second position;

FIG. 35 is a distal perspective view of another embodiment of an implantaccording to the invention, shown in a first position;

FIG. 36 is a cross-sectional view of the implant of FIG. 35;

FIG. 37 is a distal perspective view of the implant of FIG. 35, shown ina second position;

FIG. 38 is a cross-sectional view of the implant as depicted in FIG. 37;

FIG. 39-40 are cross-sectional views of another embodiment of an implantaccording to the invention, shown in first and second positions,respectively;

FIG. 41 is a distal end view of the implant of FIG. 40;

FIG. 42 is a cross-sectional view of another embodiment of an implantaccording to the invention, shown in a first position;

FIG. 43 is a distal end view of the implant of FIG. 42, shown in asecond position;

FIGS. 44-45 are cross-sectional and perspective views of a portion ofanother embodiment of an implant according to the invention;

FIGS. 46-47 are side views of the implant of FIGS. 44-45 shown in firstand second positions, respectively;

FIGS. 48-49 are end views of another embodiment of an implant accordingto the invention, shown in first and second positions, respectively;

FIGS. 50-56 are perspective views demonstrating various steps accordingto one embodiment of a method of installation of the implant of FIG. 1;

FIGS. 57-58 depict perspective views of the implant of FIG. 1 shown inan implanted position; and

FIG. 59 is a perspective view of one embodiment of a trial instrumentaccording to the invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Embodiments of the invention will now be described. The followingdetailed description of the invention is not intended to be illustrativeof all embodiments. In describing embodiments of the present invention,specific terminology is employed for the sake of clarity. However, theinvention is not intended to be limited to the specific terminology soselected. It is to be understood that each specific element includes alltechnical equivalents that operate in a similar manner to accomplish asimilar purpose.

Implants

Some embodiments of the present invention are directed to minimally orless invasive implants, in particular, interspinous process spacers.Implants in accordance with the invention may come in many shapes andsizes. The illustrative embodiments provided herein-below provideguidance as to the many types of implants that may be advantageouslyused in accordance with the present invention. In particular, theimplants are adapted such that their insertion technique (includingmethods of the present invention) is minimally or less invasive, andgenerally simpler, and/or safer than those installed in open or moreinvasive techniques. According to one aspect, implants according to thepresent invention may be advantageously inserted into a patient as anout-patient procedure.

Embodiments of the present invention include implants adapted to beplaced between first and second adjacent spinous processes. The implantsmay be adapted such that after insertion of an implant into a patient, aportion of the implant maintains a desired amount of distraction orspacing between two adjacent spinous processes. The implants or portionsthereof that substantially maintain a desired spacing between spinousprocesses are also referred to herein as “spacers.” In variousembodiments described herein, the implants may include spinous processsupport surfaces, indented portions or saddle portions spaced apart by adistance (a) (FIG. 1), which generally corresponds to a desired distancefor distraction or spacing of two adjacent spinous processes. Otherembodiments similarly provide a desired distance for distraction orspacing of two adjacent spinous processes. Depending on the materialand/or design of the implant, the desired distraction or spacingdistance may vary somewhat after insertion, for example if a patientmoves its spine into a position that causes further distraction. Forexample, in certain embodiments the implant may be resilientlycompressible or expandable in the cranial-caudal direction such that theimplant may support and or adjust to dynamic movement of the spine.Although not depicted in the figures discussed below, it is contemplatedthat embodiments of the present invention may be extended to providedistraction or spacing of more than two adjacent spinous processes.

Implants according to the present invention may be adapted to beinserted between a first and second spinous process at any region in thespine. Although typically implants according to the present inventionmay be inserted in the lumbar region, it is contemplated that it ispossible to configure inserts according to the present invention forinsertion into other regions such as for example, the thoracic orcervical region. In general, implants according to the invention mayhave varying profiles when viewed in a sagittal plane. In this regard,the implants can have varied cross-sectional shapes to conform to thevaried anatomical shapes of the interspinous spaces of the spine.

Certain embodiments of implants of the invention may secure themselvesin place without a supplemental attachment mechanism or fastening deviceattached directly to a spinous process or other portion of the spine.Alternatively, implants in accordance with the invention may be attachedto one or more spinous processes or other portion of the spine, or mayattach to itself in such a manner as to secure the implant between twoadjacent spinal processes. By way of example, implants in accordancewith the present invention may be attached to one or both spinousprocesses or other portion of the spine by one or more pins, screws,wires, cables, straps, surgical rope, sutures, elastic bands, or otherfastening devices. Other exemplary implants, attachment mechanisms, andmethods that may be utilized are disclosed in U.S. patent applicationSer. Nos. 11/366,388; 11/691,357; and 12/107,222, the entire contents ofwhich are incorporated herein by reference. “Securing” implants betweenspinous processes, does not require that the implant not move at all,but rather means that the implant does not move so far away from betweenthe spinous processes that it does not perform the function ofmaintaining a desired distraction distance or space between the adjacentspinous processes.

Implants in accordance with the present invention may be secured betweenspinous processes by methods other than using a fastening device. Forexample, according to certain embodiments, implants in accordance withthe present invention may be secured in place with respect to spinousprocesses by mechanical forces resulting from the design of the implant,including the shape itself. Exemplary implants may also be secured tospinous processes, by surface modifications to portions of the implant,such as to create frictional forces or other bonds between the implantand spinous processes. Such surface modifications may include mechanicalmodifications to the surface and/or one or more coatings. Exemplarycoatings which may be utilized include, but are not limited to, titaniumplasma sprays and chrome sprays or the like. Such mechanical forcesand/or surface modifications may be utilized in addition to, or in placeof various other attachment methods described herein.

Referring now to FIGS. 1-15, one exemplary embodiment of an implant 10according to the invention is shown for creating, increasing, ormaintaining distraction between adjacent spinous processes. In general,implant 10 is adapted and configured to be placed between adjacentspinous processes. For example, referring to FIGS. 57-58, a posteriorand side perspective view, respectively, of implant 10 is shown inimplanted positions between to two adjacent spinous processes 5. As bestseen in FIGS. 1-8, implant 10 generally comprises an elongate memberextending laterally along axis 12 from a distal or first lateral end 14to a proximal or second lateral end 16. In one embodiment, implant 10may be cannulated with a central cannula or opening 18 extending alongaxis 12. One skilled in the art may appreciate that, in operation,cannulation 18 may facilitate advancement, travel, or delivery to animplant location over a guidewire. In alternate embodiments, however,implant 10 may not be cannulated but may be generally solid. Accordingto one embodiment, implant 10 may comprise a multi-piece body with ageneral arrow or barbell-like shape, and generally includes a leadingend portion, first end portion, or distraction portion 20 adjacent firstend 14, a second end portion or trailing end portion 22 adjacent secondend 16, and a central support portion or saddle portion 24 disposedbetween the leading and trailing end portions 20, 22. As best seen inFIG. 1, support portion 24 may have a height (a) and width (d), and theimplant may have an overall length (E). As best seen in FIGS. 5 and 7,in one embodiment, saddle portion 24 has a generally circular profile orperimeter when viewed perpendicular to axis 12. In alternateembodiments, however, saddle portion need not have a circularcross-sectional profile and the cross-sectional profile may vary alongits length. For example, in one exemplary embodiment, central supportportion 24 may have a polygonal cross-sectional profile.

Trailing end portion 22 adjacent second end 16 may comprise a shoulderor flange 38 with generally frustoconical, wedged, or tapered trailingportion narrowing along axis 12 from a major or large diameter or radialdimension adjacent central support portion 24 toward the second end 16.Those skilled in the art will appreciate that such a tapered feature maybe desirable to minimize wear and trauma with adjacent soft tissueand/or bone when implant 10 is installed in a patient. In one embodimenttrailing end portion 22 may be generally symmetrical to distractionportion 20 with generally similar lateral length and taper. In alternateembodiments, however, the trailing end portion 22 need not besymmetrical whatsoever and may have any shape irrespective of thedimension of distraction portion 20.

Flange 38 generally defines a sidewall adjacent the central supportportion 24 configured and dimensioned to be positioned adjacent and/orcontact a lateral side of a spinous process when implanted. According toseveral of the embodiments depicted herein, flange 38 may have numerousfeatures to accommodate the physical anatomy of the spine when implantedin a patient. In one embodiment, shoulder portion 38 generally extendsbetween about 180 degrees and 270 degrees around axis 12, leaving aportion of the periphery without a sidewall 44 adjacent the supportportion 24. As best seen in FIG. 6, a crescent or arcuate shaped cutoutportion 39 may be disposed or formed along the perimeter of flange 38 toaccommodate the lamina and/or lamina spinous process junction region ofthe vertebra and to facilitate the anterior placement of the implantthereagainst. A flat perimeter portion 41 may be provided to minimizethe flange along the anterior side of the implant such that when implant10 is implanted in a patient, the implant may be positioned as anterioras possible. As best seen in FIGS. 57-58, in one variation, the crescentshaped cutout portion 39 is configured and dimensioned to be positionedadjacent a lamina portion of a superior vertebrae when installed. Inanother variation, flange 38 may have a thinner section 42 on the upperportion of flange 38 adjacent cutout 39. As best seen in FIGS. 57-58,such a thin section 42 may be configured and dimensioned to accommodateabutting placement against the superior spinous process when implanted.Similarly, a lower portion of flange 38 may have a chamfer 43 or angledinner surface to accommodate a lamina portion of an inferior vertebraewhen installed.

According to one variation, leading end portion 20 generally comprises apair of wing members 25 movable from a first position, shown in FIGS.1-2 and 5-6, to a second position, shown in FIGS. 3-4 and 7-8. Referringto FIGS. 1-2, wing members 25 are depicted in a first or closed positionand are configured and dimensioned to facilitate lateral insertionbetween adjacent spinous processes. In the first position, the exteriorof wing members 25 are gradually tapered from a narrow portion adjacentend 14 to a wider shoulder section 28 adjacent support portion 24. Inthis regard, when in the closed or first position, wing members 25generally form a distraction portion 20 having a frustoconical, wedged,or tapered shape widening along axis 12 from a minor diameter 26adjacent the first end 14 to shoulder 28 adjacent central supportportion 24. In one variation, shoulder 28 may be generally co-extensivewith the central support portion 24 such that a generally smoothtransition may occur as one or more spinous processes contacts and orslides along exterior wing surface during insertion of implant 10 intothe interspinous space. In alternate embodiments, shoulder 28 mayprotrude longitudinally or radially beyond the support portion 24 whenwings 25 are in the first or closed position such that anoverdistraction of the spinous processes may occur during insertion ofimplant 10 into the interspinous space. One skilled in the art mayappreciate that with the wing members in the first or closed position,such a configuration may facilitate unilateral insertion betweenadjacent spinous processes, i.e. implant 10 may be inserted betweenadjacent spinous processes from only one side.

Referring now to FIGS. 3-4, implant 10 is shown with wing members 25disposed in a second, expanded, or open position. In this regard, duringinstallation, wing members 25 are configured to remain in the first orclosed position and when implant 10 is installed in an implantedposition, wing members 25 may be selectively moved into the secondposition, as shown in FIGS. 3-4. In the second position, the wingmembers 25 generally protrude or extend radially beyond support portion24 to a greater extent than in the first position. In this regard, thewing members 25 create a flange, or lateral sidewall portion 44 oppositesidewall 44 of shoulder 38 of trailing end 22. In this position and whenimplanted, the adjacent spinous processes may be maintained between thewing members 25 and the trailing end portion 22 such that the wallsections 44 may serve to limit or block movement of implant 10 alongaxis 12 and/or dislodgement from the interspinous space. In this regard,when viewed from the side, as seen in FIG. 3, implant 10 may appear tohave a general H-like shape or a barbell-like shape, with the lateralsides 20, 22, being longitudinally spaced a distance 27, 29,respectively beyond central support portion 24. In one variation,distances 27, 29 do not need to be equal. According to one embodiment,lateral sides 20, 22 may be spaced a distance 27, 29 between about 1 mmand about 6 mm from the support portion 24. In one particularembodiment, distances 27, 29 is about 1 mm. In another embodiment,distance 23 is about 2 mm and distance 25 is about 3 mm. As shown inFIG. 3, when implant 10 is in the second position, the overall length ofimplant 10 decreases to a length (e) shorter than the overall length (E)of the implant 10 in the first position. In this regard, such ashortening of the implant along axis 12 is generally caused by themovement of wing members 25 in the direction of arrows 31 shown in FIG.3.

Referring now to FIG. 8, in the second position, wings 25 may abutand/or intermesh at the first end 14. Those skilled in the art mayappreciate that when in such a configuration, the wing membersthemselves may function to resist any further rotation or slidingmovement of wing members 25 with respect to central portion 24 duringdeployment, and may provide additional support to resist lateral forcesthat may be placed on the wings once deployed.

Referring to FIG. 9, an exploded view of one embodiment of implant 10 isshown. According to one variation, implant 10 may comprise a multi-piecedevice generally having wing members 25, pivot pins 45, a barrel insert46, a central body 48, a flexible bumper member 50, and a rotatableinsert 52. In alternate embodiments, more or less components may beprovided to achieve similar results. In general, each wing member 25 maycomprise a cantilevered body or pivot body 47 freely rotatable orpivotable about a pivot point or pin 45 extending transversely throughthe wing member via hole 51 of wings 25. Pins 45 are generally mountedto and/or extend through holes or openings 53 provided at the distal endof barrel insert 46 such that wing members 25 may pivot or rotate withrespect to barrel insert 46 about the distal end thereof. Central body48 has an annular shape with a chamfered or angled tip portion 49 at itsdistal end to facilitate sliding and/or rotative movement of wingmembers 25 thereagainst.

Barrel insert 46 is configured and dimensioned to be received withincentral body 48 and according to one variation may be keyed with respectto the central body such that barrel insert 46 may translate linearly ormove along axis 12 but is prevented from rotating with respect to thecentral body 48. In this regard, barrel insert 46 may have ears or ledgeportions 54 along a portion of its length configured and dimensioned tofit or ride within grooves 56 provided within the interior of centralbody 48 (FIG. 14). A pair of cantilevered flexible arm sections 58 maybe provided along a portion of its length to facilitate removal ofbarrel insert 46 from central body 48 after assembly. In this regard,when wing members 25 of implant 10 are in a first position, such asshown in FIG. 2, a removal tool (not shown) may be inserted throughopenings 59 to depress arms 58 and central body 48 may be slidablyremoved from the back or proximal end of barrel insert 46. As shown inFIGS. 12-13, one or more prongs or protrusions 60 may extend radiallyoutward from the proximal or back end of barrel insert 46 to engage withrotatable insert 52. In one variation, three protrusions 60 may beangularly spaced about the proximal end of barrel 46.

A rotatable insert 52 may be provided adjacent the proximal or secondend 16. As shown in FIG. 15, insert 52 may have one or more spiralgrooves 62 to accommodate protrusions 60 at the proximal or back end ofbarrel insert 46. In this regard, bayonet like openings 64 may beprovided at the distal end of insert 52 to accommodate protrusions 60during assembly. Rotatable insert 52 may be axially fixed within centralbody 48 yet freely rotatable with respect thereto. When assembled, theback or proximal end of barrel 46 may ride in groove 62 of rotatableinsert 52 and when insert 52 is rotated with respect to the central body48, the barrel insert 46 may be drawn or moved in the proximal directionalong axis 12 towards the second end 16. The pivot pins 45 located atthe distal end of barrel insert 46 will be correspondingly drawn ormoved in the proximal direction along axis 12 causing the pivot axis 51of wing members 25 to move and causing the wing members 25 to engage thecentral body 48. In this regard, wing members 25 are configured anddimensioned to be pivotable about a moving axis of rotation. In onevariation, spiral groove 62 may extend one quarter of a revolution or 90degrees about rotatable insert 52 such that a user may cause the wingmembers to completely deploy upon one quarter turn of rotatable insert52.

According to one embodiment, protrusions 60 may have a rounded sectionor bump 66 along its periphery to facilitate contact and/or engagementwith a correspondingly shaped indentation 68 provided along the profileof groove 62. In this regard, when bump 66 engages indentation 68 a usermay be provided with tactile and/or audible feedback indicating theposition of the barrel with respect to the rotation insert. In onevariation, indentation 68 is proved adjacent the proximal end of groove62 such that a user may be indicated that barrel 46 is drawn backproximally as far as possible and in accord therewith, the wing members25 are completely deployed. Those skilled in the art may appreciate thedesirability of such a feature, especially when an implant may be usedpercutaneously, minimally invasively, or in any procedure with limitedability for direct visualization of the implant during implantation. Itmay be appreciated that such a bump and indentation feature may alsoserve as a frictional rotation lock once engaged since a slightlygreater rotational force must be applied to overcome the frictionalengagement when reversing the rotational direction of insert 52. In thisregard, the rotational lock may limit and/or prevent wing members 25from undesirably moving back into the first or collapsed position onceimplant 10 is implanted in a patient.

As best seen in FIGS. 10-11, one embodiment of a wing member 25according to the invention is shown having a generally shell-like shape.In one variation, the exterior or outwardly facing surface 70 of wingmembers 25 is generally convex and may have a first ramped or taperedsection 72 and a generally flatter second ramped tapered section 74. Inthis regard, such a smooth, ramped, and/or tapered exterior generallyfacilitates direct lateral insertion into an interspinous space by astraight axial pushing force along the direction of axis 12. In anothervariation, the interior, underside, or inwardly facing surface 76 ofwing members 25 is generally concave and may include a groove 78 alongits length to accommodate sliding movement with respect to central body48. According to one variation, wing members 25 may be moved toward thesecond position by moving barrel insert 46 in the proximal directionalong axis 12. When wing members 25 are moved from the first position tothe second position, the underside 76 of each wing member 25 isgenerally rotated or moved to face the central support portion 24 andthe undersurface 76 forms the sidewall section 44. In this regard, wings25 may be attached to implant 10 such that when in a second position,the interior or inwardly facing surface 76 is generally perpendicular tosupport portion 24 to create a larger lateral barrier, blocking portion,or wall 44 adjacent central support portion 24.

In operation, implant 10 may be first inserted over a guidewire into aspace between spinous processes. In this regard, when implant 10 isadvanced over a guidewire, the guidewire generally extends within thecentral cannula 18 and contacts the tail portion 80 of each wing memberand the tail portion 80 is forced radially outward, causing the tipportion 82 to pivot inward and/or remain in the first position. Oneskilled in the art may appreciate that utilizing such a configuration,the wing members 25 may remain in a first position to facilitateimplantation over a guidewire and then once the guidewire is removed,the wing members may be selectably moved to the second position to forma larger lateral barrier, wall, or blocking portion adjacent centralsupport portion to limit or reduce the possibility of lateral migrationof implant 10 in the body.

Once installed into the desired position, the guidewire may be removedand the wing members may be deployed or moved to the second position byrotating insert 52 with respect to central body 48. When rotation insert52 is turned with respect to central body 48, an axial force istransmitted to the barrel insert to move the barrel insert 46 in theproximal direction to draw the pivot pins toward the second lateral end16. A tip portion 82 of one side of the wing body 47 contacts centralbody 48 to cause an opposite tail portion 80 of each wing member 25 topivot about point 51 toward the second position. The inner tail surfaces76 of wing members 25 ride along the chamfered tip 49 of central body 48which acts a ramp to force the wings to rotate about pivot point 51 andswing outward and move to the second position. In alternate embodiments,alternative mechanisms may be utilized to achieve the aforementionedresult. For example, in one alternative a torsion spring may bepositioned adjacent pivot point 51 to bias the wing members 25 towardthe second position. Also, in alternative embodiments, the shapes anddimensions of wing members may be altered as desired.

According to one aspect of this embodiment explained above, the wingmembers 25 swing outward with the tips 82 generally moving away from thecenter of the implant. In this regard, the tips 82 are generallyconfigured to move up and under any tissue or muscle that may beabutting against the adjacent spinous processes. Those skilled in theart may appreciate the advantageous nature of such a feature. Inparticular, such outwardly swinging wing movement may be appreciated torequire less activation force and facilitate tissue preservation ascompared to alternative wing movements. For example, certain inwardswinging movements could easily cause tissue to become trapped betweenthe implant sidewalls and the spinous process and/or cause tissuedamage.

Referring to FIG. 3, in one embodiment, one or more sockets, grooves orindentations 37 may be provided on the proximal end of implant 10 andangularly spaced about the periphery thereof to receive an installationor driving tool such as a crucifix shaped driver tool. In alternateembodiments, any other known rotational driving tools and engagementmeans may also be used, including but not limited to, a flat driver, astar shaped driver, or a threaded driver, among others. As best seen inFIG. 5, indentations 37 may be spaced along the perimeter of implant 10to facilitate insertion with a cannulated driver tool over a guidewireextending through cannula 18. The proximal end of rotatable insert 52may have similarly spaced grooves around the proximal perimeter thereofwhich may be accessed by a concentric rotation driving tool. In thisregard, rotatable insert 52 may be rotated relative to central body 48to, for example, deploy wing members 25. In one variation, a laterallyfixed engagement between the tool and the implant may be provided sothat the implant does not dislodge from the trailing end and mayefficiently transfer the rotational forces applied on the tool to theimplant during installation. One skilled in the art may appreciate thata threaded connection may also facilitate the removal of implant 10 fromthe body of a patient should a surgeon so desire.

In some embodiments, all or a portion of implant 10 may be resilientlycompressible or expandable in the cranial-caudal direction such that theimplant may support and or adjust to dynamic movement of the spine. Forexample, according to one embodiment, a flexible bumper member 50 may beprovided to at least partially cushion the compression of adjacentspinous processes. In one variation, the bumper member 50 may comprise acylindrical sleeve provided to extend around the periphery of centralsupport portion 24. In some embodiments, the bumper member may beintegrated into the support portion and in alternate embodiments thebumper member may be fit over the support portion. In one variation, thebumper member may be made from a biocompatible polyurethane, elastomer,or other similar material. In still other embodiments, implant 10 may bemade from varying materials along its length, such that for example thecentral support portion may be made from a resilient material, such aspolyurethane, elastomer or the like, and the end portions may be madefrom a rigid material, such as titanium or the like.

The implant itself may serve to dilate or distract the spinous processesas it is being inserted and/or after insertion. For example, inembodiments in which the implant is similar to that depicted in FIGS.1-15, the first end 14 of implant 10 may be initially inserted oradvanced laterally between compressed adjacent spinous processes asshown in FIGS. 16-20, for example. The supraspinous ligament may or maynot be removed. In an initial pre-implantation condition, shown in FIG.16, the adjacent spinous processes 5 may be compressed or narrowlyspaced such that the initial space or longitudinal distance 90 betweenthe processes may be about equal to or slightly larger or smaller thandistance (b) of implant 10. During lateral insertion of the implant, oneor more ramp or tapered surfaces or portions of the implant may contactone or both of the spinous processes 5 and may initially distract theprocesses a distance (b). As the implant is advanced laterally, the rampor tapered shape of the distraction portion may distract the spinousprocesses further apart from one another, until the implant is advancedlaterally into an implanted position (FIGS. 19-20) and the spinousprocesses are fitted into the central support portion 24 of the implant10. In operation, the ramp surfaces engage the adjacent spinousprocesses as the implant is laterally advanced to act or perform in acam-like manner to translate the lateral force to separate the spinousprocesses in the longitudinal or cranial-caudal direction as the implantis advanced. The maximum distraction of spinous processes by the implant10 is distance (c) depicted in FIG. 18. According to one embodiment,distance (c) is greater than distance (a) such that the spinousprocesses 5 may be slightly “over distracted” during installation. Inthis regard, one skilled in that art may appreciate that such an overdistraction may facilitate enhanced tactile feedback to a surgeon duringinstallation as the spinous processes drop into the central supportportion to signify a desired lateral placement in the patient with thespinous processes positioned within the central support portion. Oncethe implant is laterally advanced to the position shown in FIG. 19, theflange 38 of trailing end portion 22 may contact and/or abut the lateralside of the spinous processes to prevent further lateral translation androtation insert 52 of implant 10 may be subsequently rotated about onequarter turn or about 90 degrees to deploy the wing members 25 into thefinal implantation position as shown in FIG. 20. In this regard, in thefinal implantation position, the shoulder wall sections 44 may contactthe lateral sides of the spinous processes to limit or block movement ofthe implant along axis 12 and/or dislodgement from the interspinousspace. Also, once the implant is implanted and after the spinousprocesses are fitted into the central support portion 24, the implantmay maintain the spinous processes in a distracted or spaced condition,for example where the distance (a) of the implant is greater than apre-implantation distance between the spinous processes.

Referring to FIGS. 21-25, another embodiment of an implant 100 accordingto the invention is shown. Implant 100 is similar to implant 10described above except wing members 25 may additionally include aramped, toothed, fluted, threaded or grooved section 32. According toone embodiment, grooved section 32 generally comprises helical or spiralramp peaks 36 extending from first end toward support portion 24. Ramppeaks 36 of section 32 may have a separation sufficiently narrow toprevent the adjacent spinous process from riding within the grooves 34defined between the peaks 36. In this regard, when wing members are inthe first position, as shown in FIGS. 21-22, the peaks 36 may beconfigured and dimensioned to engage or contact a portion of the spinousprocess bone and cause the implant 100 to advance or travel along axis12 when implant 100 is rotated. In one variation, distraction portion 20is configured and dimensioned such that when implant 100 is rotatedabout axis 12, the adjacent spinous processes ride upon ramp peaks 36and are distracted or separated apart as implant 10 is advancedlaterally along axis 12 during implantation. The rate at which thedistraction occurs may be readily controlled by a surgeon by controllingthe rate of rotation of implant 10, so that the surgeon may advanceimplant 100 along axis 12 as slow or as fast as desired. In this regard,implant 100 may be characterized as self-distracting, as the implantitself distracts or separates the spinous processes as it is beingimplanted, i.e. without requiring an additional distraction step ordevice.

Referring to FIGS. 23-26, implant 100 is shown with wing members 25 in asecond or expanded condition. Similar to implant 10, described above,once the implant is laterally advanced to a desired installationposition, the flange 38 of trailing end portion 22 may contact and/orabut the lateral side of the spinous processes to prevent furtherlateral translation and rotation insert 52 of implant 100 may besubsequently rotated about one quarter turn or about 90 degrees todeploy the wing members 25 into the second position as shown in FIGS.23-26. In this regard, in the final implantation position, the shoulderwall sections 44 may contact the lateral sides of the spinous processesto limit or block movement of the implant along axis 12 and/ordislodgement from the interspinous space. As with implant 10 describedabove, once the implant is implanted and after the spinous processes arefitted into the central support portion 24, the implant may maintain thespinous processes in a distracted or spaced condition, for example wherethe distance (a) of the implant is greater than a pre-implantationdistance between the spinous processes. Also as described above, thewing members 25 swing outward with the tips 82 generally moving awayfrom the center of the implant. In this regard, the tips 82 aregenerally configured to move up and under any tissue or muscle that maybe abutting against the adjacent spinous processes.

Referring now to FIGS. 27-34, another embodiment of an interspinousprocess implant 110 is shown. Implant 110 is similar to implant 100described above, however, in this embodiment, a pair of thin slidablewing fingers 112 are provided within the distraction portion 20. Likeimplant 100 described above, distraction portion 20 comprises a includea ramped, toothed, fluted, threaded or grooved section 32 disposed aboutaxis 12 and extending from a narrow first end 14 toward central supportportion 24. In this embodiment, wing fingers 112 are movable from afirst position, shown in FIGS. 27-30, to a second position, shown inFIGS. 31-34. Referring to FIGS. 27-30, wing fingers 112 are depicted ina first or closed position and are configured and dimensioned tofacilitate lateral insertion between adjacent spinous processes. In thefirst position, the exterior of wing fingers 112 are generally recessedwithin distraction portion 20. One skilled in the art may appreciatethat with the wing fingers in the first, or closed, position, such aconfiguration may facilitate unilateral insertion between adjacentspinous processes.

Referring to FIGS. 31-34, implant 110 is shown with wing fingers 112 ina second position. Similar to implants 10 and 100, described above, oncethe implant is laterally advanced to a desired installation position,the flange 38 of trailing end portion 22 may contact and/or abut thelateral side of the spinous processes to prevent further lateraltranslation and rotation insert 52 of implant 110 may be subsequentlyrotated about one quarter turn or about 90 degrees to deploy the wingfingers 112 into the second position as shown in FIGS. 31-34. In thisregard, in the final implantation position, the shoulder wall sections44 may contact the lateral sides of the spinous processes to limit orblock movement of the implant along axis 12 and/or dislodgement from theinterspinous space. Also, once the implant is implanted and after thespinous processes are fitted into the central support portion 24, theimplant may maintain the spinous processes in a distracted or spacedcondition, for example where the distance (a) of the implant is greaterthan a pre-implantation distance between the spinous processes. As withimplants 10 and 100 described above, the wing fingers 112 swing outwardwith the tips 82 generally moving away from the center of the implant.In this regard, the tips 82 are generally configured to move up andunder any tissue or muscle that may be abutting against the adjacentspinous processes.

Referring now to FIGS. 35-38, another embodiment of an interspinousprocess implant 120 is shown. Implant 120 is similar to implant 110described above, however, in this embodiment, a pair of wing fingers ortabs 122 are actuatable by a rotatable gear barrel insert 124. Barrelinsert 124 has a worm gear adjacent its distal portion that isconfigured and dimensioned to engage teeth or prongs 126 on the interiorof tabs 122. When barrel insert 124 is rotated, tabs 122 may swinginward toward the second position shown in FIGS. 37-38. Like implant 100described above, distraction portion 20 comprises a include a ramped,toothed, fluted, threaded or grooved section 32 disposed about axis 12and extending from a narrow first end 14 toward central support portion24. In this embodiment, wing tabs 122 are movable from a first position,shown in FIGS. 35-36, to a second position, shown in FIGS. 37-38.Referring to FIGS. 35-36, wing tabs 122 are depicted in a first orclosed position and are configured and dimensioned to facilitate lateralinsertion between adjacent spinous processes. In the first position, theexterior of wing tabs 122 are generally recessed within distractionportion 20. One skilled in the art may appreciate that with the wingfingers in the first, or closed, position, such a configuration mayfacilitate unilateral insertion between adjacent spinous processes.

Referring to FIGS. 37-38, implant 120 is shown with wing tabs 122 in asecond position. Once the implant is laterally advanced to a desiredinstallation position, the flange 38 of trailing end portion 22 maycontact and/or abut the lateral side of the spinous processes to preventfurther lateral translation. Barrel insert 124 of implant 120 may besubsequently rotated to deploy the wing tabs 122 into the secondposition as shown in FIGS. 37-38. In this regard, in the finalimplantation position, the shoulder wall sections 44 may contact thelateral sides of the spinous processes to limit or block movement of theimplant along axis 12 and/or dislodgement from the interspinous space.Also, once the implant is implanted and after the spinous processes arefitted into the central support portion 24, the implant may maintain thespinous processes in a distracted or spaced condition, for example wherethe distance (a) of the implant is greater than a pre-implantationdistance between the spinous processes. When barrel insert 124 isrotated, tabs 122 may swing inward toward the center of the implant.

Referring now to FIGS. 39-41, another embodiment of an interspinousprocess implant 130 is shown. Implant 130 is similar to previouslydescribed implants, however, in this embodiment, a plurality of thinfingers 132 are provided within the distraction or distal portion 20. Inone variation, fingers 132 are pivotably installed adjacent distalportion 20. As best seen in FIGS. 39-40, fingers 132 may be actuated ormoved from a first position (FIG. 39) to a second position (FIG. 40) bydrawing a front or distal end portion 134 backward in a proximaldirection along axis 12. In this regard, an internal ramp portion 136may be provided to engage a tip portion of fingers 132 such that as thedistal end is drawn back, fingers 132 pivot or rotate about their base138. Similar to previously described embodiments, in a first position,fingers 138 are recessed within distal portion 20 and in a secondposition, fingers 132 extend outward to create a wall section to limitor block movement of the implant along axis 12 and/or dislodgement fromthe interspinous space.

Referring now to FIGS. 42-43, another embodiment of an interspinousprocess implant 140 is shown. Implant 140 is similar previouslydescribed embodiments, however, in this embodiment, a plurality of wingmembers 142 are pivotably mounted to a distal portion 144. Wing members142 are configured to remain recessed within distraction portion 20 in afirst position (FIG. 42). Wing members 142 are rotatable about an axisparallel to axis 12 and may be actuated by rotating the central body 146with respect to distal portion 144. When central body 146 is rotated,wing members 142 swing radially outward toward the second position shownin FIG. 43.

Referring now to FIGS. 44-47, another embodiment of an interspinousprocess implant 150 is shown. Implant 150 generally comprises first andsecond members 152, 154 having a shoulder or larger sized diameterportion 155 adjacent a generally cylindrical midsection 156. In onevariation, the first and second members may be threadably connectable.In alternate embodiments, first and second members 152, 154 maysnappably connectable. A deformable wing body 157 may be disposed aboutthe first and second members 152, 154 and wing body 157 may havebendable ends 158 having one or more flexible joints 159 thereon. Firstand second members may be concentrically connected at midsection 156such that the first and second members may be axially moveable withrespect to each other such that first and second members 152, 154 may bemoved relative to each other form a first position (FIG. 46) to a secondposition (FIG. 47) to contract or shorten the overall length of implant150. In this regard, when in the second position as shown in FIG. 47,bendable ends 158 hinge or bend at joints 159 and extend radiallyoutward in a direction transverse to axis 12 toward the second positionshown in FIG. 47. Similar to previously described embodiments, in afirst position, bendable ends 158 are retracted and in a secondposition, ends 158 extend outward to create a wall section to limit orblock movement of the implant along axis 12 and/or dislodgement from theinterspinous space.

Referring now to FIGS. 48-49, another embodiment of an interspinousprocess implant 160 is shown. Implant 160 is similar to previouslydescribed embodiments, however, in this embodiment a pair of geared pins162 are actuatable by a rotatable gear barrel insert 164. Barrel insert164 has a gear teeth profile adjacent its distal portion configured anddimensioned to engage corresponding teeth or prongs on the interior ofpins 162. When barrel insert 164 is rotated, pins 162 extend radiallyoutward in a direction transverse to central axis 12 toward the secondposition shown in FIG. 49.

According to certain embodiments of the invention, the implantsdescribed above may have a trailing end portion 22 with an externalhexagonal shaped portion to engage an installation tool such as ahexagonal socket shaped driver tool. In alternate embodiments, however,any other known rotational and/or driving tools and engagement means mayalso be used.

Kits having at least one implant such as those depicted in FIGS. 11-15,may include various sizes of implants having varying heights (a), widths(d), and overall lengths (e), for example having variations withincremental distances. In one embodiment, a system or kit may beprovided that has implants having heights (a) between about 6 mm toabout 22 mm. For example, in one variation implants having heights (a)of 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, and 20 mm may be provided.In another variation, a system or kit may be provided that has implantshaving widths (d) between about 6 mm to about 18 mm. For example, in onevariation implants having widths (d) of 8 mm, 12 mm, and 16 mm may beprovided. In yet another variation, a system or kit may be provided thathas implants having overall lengths (e) between about 20 mm and about 60mm. For example, in one variation implants having overall lengths (e) of25 mm and 50 mm may be provided.

Material

Implants in accordance with the present invention may be made of one ormore materials suitable for implantation into the spine of a mammalianpatient. Materials in accordance with the present invention may bebiocompatible with a mammalian patient and/or may have one or moresurface coatings or treatments that allow the spacers to bebiocompatible. Materials in accordance with the present invention mayinclude one or more materials having sufficient load capability and/orstrength to maintain the desired spacing or distraction between spinousprocesses. Depending on the design employed, certain embodiments mayhave components or portions made of a material having certainflexibility, as desired for the particular application. Additionally,the materials of the present invention may be made of one or morematerials that maintain their composition and shape for as long a timeas possible without degrading or decomposing or changing shape, suchthat replacement of the implant is avoided.

Suitable materials for use in accordance with the present inventionwould be known to those skilled in the art. Non-limiting examplesinclude one or more materials selected from medical grade metals, suchas titanium or stainless steel, biocompatible polymers, such aspolyetheretherketone (PEEK), ceramics, deformable materials, bone,allograft, demineralized or partially demineralized bone, allograftligament, and polyurethane (for example, for portions of the insertwhere cushioning is desired). Similarly, any fastening devices may bemade of materials having one or more of the properties set forth withrespect to the implant itself. For example, screws or pins may includetitanium and straps may include polyethylene. In some embodiments,primarily radiolucent material may be used. In this regard, radio-opaquematerial or markers may be used in combination with the radiolucentmaterial to facilitate implantation. Exemplary radio-opaque materialincludes but is not limited to titanium alloys, tantalum or other knownradio-opaque marker material. As indicated above, implants in accordancewith the present invention may have one or more portions that may havemodified surfaces, surface coatings, and/or attachments to the surface,which may assist in maintaining the spacer in a desired position, forexample by friction. Suitable surface modifications, coatings, andattachment materials would be known to those skilled in the art, takinginto consideration the purpose for such modification, coating, and/orattachment.

Methods for Treating Stenosis and Methods of Inserting an Implant

Methods are provided for treating spinal stenosis. Methods are alsoprovided for inserting an implant. These methods may include implantinga device to create, increase, or maintain a desired amount ofdistraction, space, or distance between adjacent first and secondspinous processes. The adjacent first and second spinal processes may beaccessed by various methods known by practitioners skilled in the art,for example, by accessing the spinous processes from at least onelateral side/unilateral, bilateral, or midline posterior approach.

Certain methods of the present invention include creating an incision ina patient to be treated, dilating any interspinous ligaments in aposition in which the implant is to be placed in the patient, sizing thespace between adjacent spinous processes (for example using trials), andinserting an implant of the appropriate size between the adjacentspinous processes. Methods of the present invention may include securingthe implant to one or more of the spinous processes, to one or moreother portions of the patient's spine, and/or to itself such that theimplant maintains its position between the spinous processes.

Methods of the present invention may include dilating or distracting thespinous processes apart from one another before sizing and/or beforeinserting the implant. Methods may vary depending on which implant isbeing inserted into a patient. For example, certain implants may requiredistracting the spinous processes apart before inserting the implant,while other implants may themselves dilate or distract the spinousprocesses while inserting the implant. In embodiments where the implantsthemselves dilate or distract the spinous process, the implant may have,for example, a predetermined shape to dilate, distract, or otherwisemove or separate apart adjacent spinous processes such as a cam orcam-like profile, it may have a distraction device that is deployed,and/or it may have a tapered expander to distract an opening between theadjacent spinous processes or other features to facilitate distractionof the adjacent spinous processes.

According to certain embodiments, spacers may be placed between thespinous processes anterior to the supraspinous ligament, avoiding thenerves in the spinal canal. The procedure may be performed under localanesthesia. According to one method for surgical procedures, in which animplant is being inserted into the lumbar region, the patient may beplaced in a left or right lateral decubitus position with the lumbarspine flexed or in another flexed position. According to one method, asurgeon may desire to use fluoroscopy to align in parallel the adjacentvertebral bodies corresponding to the adjacent spinous processes togauge the desired distraction distance.

According to certain embodiments, one or more probes may be used tolocate the space between the spinous processes. Depending on the designof the spacer to be inserted, the space may be widened, for example witha dilator before inserting the implant.

Referring to FIGS. 50-57, one embodiment of a surgical method accordingto the invention for implanting an implant 10 in the spine is disclosed.According to this embodiment, the adjacent first and second spinalprocesses 5 may be accessed from one lateral side through a minimally orless invasive procedure. In this regard, according to certain methods ofthe invention, a unilateral approach may be used to install implant 10without removal of the supraspinous ligament. In this method, as shownin FIG. 50, a guide wire 202, such as a K wire, is inserted laterallythrough the skin and into the interspinous space 204. According to onemethod, a working portal may be created concentric to the guidewire 202,as shown in FIGS. 51-52, by inserting a series of sequentially largerdiameter tubes 206, 208, 210, 212, 214 to dilate the tissue surroundingguidewire 202. Referring to FIG. 53, once a dilating tube having asufficiently large inner diameter to accommodate implant 10 ispositioned about guidewire 202, the smaller diameter tubes 206, 208,210, 212 may be withdrawn, leaving the guidewire 202 and the outer tube214. Referring to FIG. 54, one or more trials 215 may then be insertedto appropriately size the interspinous space 204 and the trials 215 mayalso be utilized to dilate interspinous ligaments. In one exemplaryembodiment, a generally cannulated cylindrical trial 215, shown in FIG.54, may be utilized to size the space between adjacent processes 5.Referring to FIG. 59, an alternate embodiment of a trial 216 that may beused is shown which may comprise a ramped tip portion 217 adjacent itsdistal end and multiple longitudinal indentations or markings 218 on atleast a portion of central portion 219 and may provide visual indicationwhen viewed under fluoroscopy of the width of the spinous processes andfacilitate the surgeon's selection of an appropriately sized implant.Similarly, the appropriate diameter of central portion 219 of trial 216may be selected to gauge the amount of distraction desired. In thisregard, the spacing of the spinous processes may be viewed underfluoroscopy to facilitate the surgeon's selection of an appropriatelysized implant. Finally, an implant of the appropriate size may beinserted between the adjacent spinous processes.

Referring to FIGS. 55-56, one exemplary embodiment of a method ofinstalling implant 10 is shown. Implant 10 is advanced over guidewire202 through cannulation 18 to the interspinous space 204. During lateralinsertion of the implant between the spinous processes, one or more rampsurfaces or portions of the implant may contact one or both of thespinous processes 5 and may initially distract the processes. Implant 10may be rotated to further advance implant 10 between the spinousprocesses and, the wedged or tapered shape of the distraction portion 20may distract the spinous processes further apart from one another, untilthe implant is rotated and advanced laterally into an implanted position(FIGS. 55-58) with the distraction portion 20 positioned on thecontralateral side of the spinous processes and the spinous processesare fitted into the central support portion 24 of the implant 10.Referring to FIGS. 57-58, once implant 10 is installed, the guidewiremay be removed through the cannulation leaving the implant 10 in theinterspinous space.

While the invention herein disclosed has been described by means ofspecific embodiments and applications thereof, numerous modificationsand variations can be made thereto by those skilled in the art withoutdeparting from the scope of the invention.

What is claimed is:
 1. An implant for positioning between adjacentspinous processes comprising: an elongate body having a longitudinalaxis, the elongate body including a leading end portion, a trailing endportion, and a central support portion disposed between the leading andtrailing end portions, wherein the trailing end portion includes aflange defining a sidewall configured and dimensioned to contact atleast one of the adjacent spinous processes; one or more tabs attachedto the leading end portion; and a gear barrel insert extending throughthe trailing end portion and the central support portion, wherein theone or more tabs are actuatable by the rotatable gear barrel insert suchthat when the gear barrel insert is rotated, the tabs extend outwardlyfrom the leading end portion, and wherein the leading end portionextends from a proximal portion to a distal portion, and the one or moretabs are rotatably attached to the proximal portion of the leading endportion.
 2. The implant of claim 1, wherein the gear barrel insertincludes a worm gear.
 3. The implant of claim 2, wherein the worm gearengages prongs on the one or more tabs on the leading end portion. 4.The implant of claim 1, wherein the leading end portion includes agrooved section.
 5. The implant of claim 1, wherein the one or more tabsinclude a pair of tabs.
 6. The implant of claim 1, wherein the one ormore tabs have a first position where the one or more tabs are generallyrecessed within the leading end portion and the implant is configured tofacilitate lateral insertion between the adjacent spinous processes. 7.The implant of claim 6, wherein the one or more tabs have a secondposition where the one or more tabs extend outwardly, and the adjacentspinous processes are maintained between the one or more tabs of theleading end portion and the flange of the trailing end portion, therebylimiting movement of the implant along the longitudinal axis.
 8. Animplant for positioning between adjacent spinous processes comprising:an elongate body having a longitudinal axis, the elongate body includinga leading end portion and a trailing end portion, wherein the trailingend portion includes a flange configured and dimensioned to contact atleast one of the adjacent spinous processes; one or more tabs attachedto the leading end portion; and a gear barrel insert extending throughthe trailing end portion, wherein the one or more tabs are actuatable bythe rotatable gear barrel insert such that when the gear barrel insertis rotated, the tabs extend outwardly from the leading end portion, andwherein the leading end portion extends from a proximal portion to adistal portion, and the one or more tabs are rotatably attached to theproximal portion of the leading end portion.
 9. The implant of claim 8,wherein the gear barrel insert includes a worm gear.
 10. The implant ofclaim 9, wherein the worm gear engages prongs on the one or more tabs onthe leading end portion.
 11. The implant of claim 8, wherein the leadingend portion includes a grooved section.
 12. The implant of claim 8,wherein the one or more tabs include a pair of tabs.
 13. The implant ofclaim 8, wherein the one or more tabs have a first position where theone or more tabs are generally recessed within the leading end portionand the implant is configured to facilitate lateral insertion betweenthe adjacent spinous processes.
 14. The implant of claim 13, wherein theone or more tabs have a second position where the one or more tabsextend outwardly, and the adjacent spinous processes are maintainedbetween the one or more tabs of the leading end portion and the flangeof the trailing end portion, thereby limiting movement of the implantalong the longitudinal axis.
 15. An implant for positioning betweenadjacent spinous processes comprising: an elongate body having alongitudinal axis, the elongate body including a leading end portion, atrailing end portion, and a central support portion disposed between theleading and trailing end portions, wherein the trailing end portionextends from a proximal end to a distal end, and the trailing endportion includes a flange proximate to the distal end; one or more tabsattached to the leading end portion; and a gear barrel insert extendingthrough the trailing end portion, wherein the one or more tabs areactuatable by the rotatable gear barrel insert such that when the gearbarrel insert is rotated, the tabs extend outwardly from the leading endportion, wherein the one or more tabs have a first position where theone or more tabs are generally recessed within the leading end portionand the implant is configured to facilitate lateral insertion betweenthe adjacent spinous processes, wherein the one or more tabs have asecond position where the one or more tabs extend outwardly, and theadjacent spinous processes are maintained between the one or more tabsof the leading end portion and the flange of the trailing end portion,thereby limiting movement of the implant along the longitudinal axis,and wherein the leading end portion extends from a proximal portion to adistal portion, and the one or more tabs are rotatably attached to theproximal portion of the leading end portion.
 16. The implant of claim15, wherein the gear barrel insert includes a worm gear sized andconfigured to engage prongs on the one or more tabs on the leading endportion.
 17. The implant of claim 15, wherein the leading end portionincludes a grooved section extending from the distal portion toward thecentral support portion.